Quiet vacuum cleaner

ABSTRACT

A light-weight, quiet vacuum cleaner assembly for a backpack vacuum cleaner includes an air inlet for communicating with a vacuum cleaner hose and a filter; a vacuum motor for drawing air through the vacuum cleaner hose, air inlet, and filter; a quiet exhaust assembly module in communication with the vacuum motor for expelling and quieting exhaust from the vacuum motor, and wherein the vacuum cleaner assembly weighs 2-12 lbs. and includes a flow rate (CFM) to noise (dbA) ratio (flow rate/noise) of at least 0.6.

BACKGROUND

1. Field of the Invention

The present invention relates, in general, to vacuum cleaners, and, inparticular, to backpack vacuum cleaners.

2. Background of the Invention

It is well-known that vacuum cleaning efficiency has been improvedthrough the use of backpack vacuum cleaners. A backpack vacuum cleanerincludes a backpack assembly, similar to that used in a hiking backpack,where the vacuum cleaner assembly is carried by a backpack frame of thebackpack assembly. A vacuum cleaner hose extends from a top of thevacuum cleaner assembly and is connected to a vacuum cleaner wand. Adistal end of the vacuum cleaner wand includes a vacuum cleaner floortool. In use, the cleaner carries the backpack vacuum cleaner on his orher back using the backpack assembly, and directs the vacuum cleanertool for cleaning the floor surface through the wand. Historically, muchof the cleaning performed using backpack vacuum cleaners such as thatdone in office buildings or other commercial settings was done at nighttime, by night-time cleaning personnel and janitors. Noise made by thebackpack vacuum cleaners was not that big of an issue because mostworkers and visitors were not present during the vacuum cleaning, so thenoise would not bother workers in the office buildings or othercommercial settings. However, more recently, there is a trend to cleanduring the daytime, when workers and visitors in the office buildings orother commercial settings are present. One of the complaints by workersand visitors in the office buildings or other commercial settings ofvacuum cleaning is the noise. The noise sources are noises associatedwith the motor and air movement noise at the vacuum tools and exhaust.

Motor noise has been addressed in the past by placing sound absorbingmaterials in the flow path. This reduces the system performance to anunacceptable level and adds weight to the vacuum cleaner. By restrictingthe flow path in this manner the motor is susceptible to overheatingbecause it is not getting sufficient air for cooling.

Therefore, a need exists for a vacuum cleaner, especially a backpackvacuum cleaner, that overcomes the problems with prior art vacuumcleaners, especially the problems with prior art backpack vacuumcleaners.

SUMMARY

The backpack vacuum cleaner of the present invention is light-weight andsignificantly reduces the noise levels associated with the motor and airmovement noise at the vacuum tools and exhaust while maintaining goodsystem performance. The vacuum cleaner maintains large cross-sectionalareas for exhaust flow, allowing sufficient air flow to provide therequired cooling for the motor. The vacuum cleaner also directs the airflow to unique foam surfaces to obtain the required sound deadening.

An aspect of the invention involves a light-weight, quiet vacuum cleanerassembly for a backpack vacuum cleaner including a backpack assembly forcarrying the vacuum cleaner assembly on a user's back, a vacuum cleanerhose for vacuuming debris from a surface, and a filter for filtering outvacuumed debris. The light-weight, quiet vacuum cleaner assemblyincludes an air inlet for communicating with the vacuum cleaner hose andthe filter; a vacuum motor for drawing air through the vacuum cleanerhose, air inlet, and filter; a quiet exhaust assembly module incommunication with the vacuum motor for expelling and quieting exhaustfrom the vacuum motor, and wherein the vacuum cleaner assembly weighs2-12 lbs. and includes a flow rate (CFM) to noise (dbA) ratio (flowrate/noise) of at least 0.6.

Another aspect of the invention involves a light-weight, quiet vacuumcleaner assembly for a backpack vacuum cleaner including a backpackassembly for carrying the vacuum cleaner assembly on a user's back, avacuum cleaner hose for vacuuming debris from a surface, and a filterfor filtering out vacuumed debris. The light-weight, quiet vacuumcleaner assembly includes an air inlet for communicating with the vacuumcleaner hose and the filter; a vacuum motor for drawing air through thevacuum cleaner hose, air inlet, and filter; a quiet exhaust assemblymodule in communication with the vacuum motor for expelling and quietingexhaust from the vacuum motor, and wherein the vacuum cleaner assemblyweighs 2-12 lbs. and includes a suction (in. (H₂O)) to noise (dbA) ratio(suction/noise) of at least 0.6.

Another aspect of the invention involves a light-weight, quiet vacuumcleaner assembly for a backpack vacuum cleaner including a backpackassembly for carrying the vacuum cleaner assembly on a user's back, avacuum cleaner hose for vacuuming debris from a surface, and a filterfor filtering out vacuumed debris. The light-weight, quiet vacuumcleaner assembly includes an air inlet for communicating with the vacuumcleaner hose and the filter, the air inlet including an intake area; avacuum motor for drawing air through the vacuum cleaner hose, air inlet,and filter; a quiet exhaust assembly module in communication with thevacuum motor for expelling and quieting exhaust from the vacuum motor,and wherein the quiet exhaust assembly module includes a stage ofexhaust openings having a total area and the ratio of the total area ofthe stage of exhaust openings to the intake area of the air inlet is atleast 3:1.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of the present invention, both as to its structure andoperation, may be gleaned in part by the accompanying drawings, in whichlike reference numerals refer to like parts, and in which:

FIG. 1 is a perspective view of an embodiment of a quiet backpack vacuumcleaner with a vacuum cleaner hose, vacuum cleaner wand, and vacuumcleaner floor tool attached and the quiet backpack vacuum cleaner shownin use on the back of a user;

FIG. 2 is perspective view of the backpack vacuum cleaner of FIG. 1;

FIG. 3 is front elevational view of the backpack vacuum cleaner of FIG.1 with the back strap system, power cord assembly, two-speed switchassembly, and paper filter bag hidden for clarity;

FIG. 4 is a front elevational view of a quiet exhaust assembly of thebackpack vacuum cleaner with the rest of the backpack vacuum cleanershown in phantom;

FIG. 5 is an enlarged front elevational view of the quiet exhaustassembly module of FIG. 4 with the exhaust air flow path shown; and

FIG. 6 is an exploded perspective view of the quiet exhaust assemblymodule of FIGS. 4 and 5.

DETAILED DESCRIPTION

With reference to FIGS. 1-6, and initially FIGS. 1-3, an embodiment of aquiet backpack vacuum cleaner 100 will be described.

Although the quiet vacuum cleaner 100 is shown and described as abackpack vacuum cleaner, the features of the vacuum cleaner 100 thatmake it a quiet, high-performance vacuum cleaner may be applied toadditional types of vacuum cleaners such as, but not by way oflimitation, canister vacuum cleaners and upright vacuum cleaners.

After reading this description it will become apparent to one skilled inthe art how to implement the invention in various alternativeembodiments and alternative applications. However, although variousembodiments of the present invention will be described herein, it isunderstood that these embodiments are presented by way of example only,and not limitation. As such, this detailed description of variousalternative embodiments should not be construed to limit the scope orbreadth of the present invention as set forth in the appended claims.

With reference to FIG. 1, the quiet backpack vacuum cleaner 100 includesa vacuum cleaner assembly 110 that is carried on a user's back via abackpack assembly 120. A vacuum cleaner hose 130 extends from a top ofthe vacuum cleaner assembly 110 and is connected to a vacuum cleanerwand 140. A distal end of the vacuum cleaner wand 140 includes a vacuumcleaner floor tool 150, which engages the carpet or other floor surfacefor cleaning the same.

With reference additionally to FIG. 2, the backpack assembly 120includes a backpack strap system 160 connected to a vacuum cleanersupport 170, which carries the vacuum cleaner assembly 110. The backpackstrap system 160 includes shoulder straps 180 and a waist belt 190.

The vacuum cleaner assembly 110 includes a main housing assembly 200, atop cap hose and air inlet 210 at a top end, and an opposite exhaust end220. A two-speed switch assembly with switch box 230 and a power cordassembly 240 are connected to a lower electrical section 260 (FIG. 3) ofthe vacuum cleaner assembly 110 through respective cords.

With reference additionally to FIG. 3, the vacuum cleaner assembly 110includes an upper filter section 250 and a lower electrical section 260.The upper filter section 250 includes an intake filter and refuse bag265, and a motor intake filter 280. A lower portion of the upper filtersection 250 and the lower electrical section 260 carry a quiet exhaustassembly module 270.

With reference to FIGS. 4-6, an embodiment of the quiet exhaust assemblymodule 270 will be described in more detail. The quiet exhaust assemblymodule 270 includes a vacuum motor 290, an annular gasket 300, a motorhousing 310, a quiet module housing 320, acoustic panel 330, an annulardirector plate 340, an annular foam air diffuser 350, an annularacoustic panel 360, and a quiet module cap 370. Each of these quietexhaust assembly module components will now be described in turn below.

The vacuum motor 290 is a two-stage vacuum motor having a cylindricalhead with an underside.

The annular gasket 300 is a neoprene gasket with an adhesive on oneside. The annular gasket 300 is disposed between the underside of thecylindrical head of the vacuum motor 290 and an upper surface of themotor housing 310.

Threaded fasteners 380 are used to attach the vacuum motor 290 to themotor housing 310.

The motor housing 310 has a generally cylindrical wall 382 with Stage 1elongated lateral slots 384 near a bottom of the motor housing 310. Inthe embodiment shown, the motor housing 310 includes four (4) Stage 1slots 384 with three (3) of the slots having a dimension of 3.25 in.×0.5in. (3 Slots @ 3.25″×0.5″=4.875 sq. in.), and the last slot having adimension of 2.25 in.×1.0 in. (1 Slot @ 2.25″×1.0″=2.25 sq. in.). Stage1 air flow occurs through these slots 384. The total area of the Stage 1slots 384 is 4.875 sq. in.+2.25 sq. in.=7.125 sq. in. The bottom of themotor housing 310 includes a plurality of ribs 386 extending outwardlyfrom the wall 382. The ribs 386 include threaded bosses.

Threaded fasteners 390 threadably engage the threaded bosses of the ribs386 to attach the quiet module housing 320 to the motor housing 310.

The quiet module housing 320 includes a top surface 392 withstar-shaped, radiating ridges extending therefrom. The top surface 392of the quiet module housing 320 forms the bottom or floor of the motorhousing 310 when the quiet module housing 320 is connected to the motorhousing 310. The quiet module housing 320 has a frustoconical wall 394with Stage 2 elongated lateral slots 396 near a top of the quiet modulehousing 320. In the embodiment shown, the quiet module housing 320includes four (4) Stage 2 slots 396 having a dimension of 3.00 in.×0.5in. (4 Slots @ 3.00″×0.5″=6.0 sq. in.). Stage 2 air flow occurs throughthese slots 396. As indicated above, the total area of the Stage 2 slots396 is 6.0 sq. in.

The acoustic panel 330 includes two half-cylindrical members with anouter surface 398. The acoustic panel 330 is made of a unique,light-weight, high-temperature, fire-retardant foam material. The foammaterial is produced in flat sheets. An adhesive is added to a side of aflat 0.032 in. polycarbonate sheet, and the polycarbonate sheet islaminated to a side of the flat sheet of foam material. Two flat sheetsof foam material and polycarbonate are bent into the half-cylinderconfiguration shown, with the polycarbonate sheet on the outer side ofthe acoustic panel 330. The two half-cylindrical members are placedtogether to form a cylinder around the quiet exhaust assembly module270, as shown in FIG. 5. The hoop stress in the polycarbonate sheet andacoustic panel 330 cause the acoustic panel 330 to be held in place overthe motor housing 310, quiet module housing 320, annular director plate340, annular foam air diffuser 350, annular acoustic panel 360, andquiet module cap 370 without any adhesive. The unique, light-weight,high-temperature, fire-retardant foam material of the acoustic panel 330provides maximum attenuation of the sound waves in the quiet exhaustassembly module 270. The foam material used in the acoustic panels 330is a high-performance polyimide foam sold as type HT-340 under the nameSolimide® by INSPEC FOAMS, INC. of Plano, Tex. For mechanicalproperties, the foam material has a density (ASTM D 3574, Test A) of 0.4lb/ft³, and a tensile strength (ASTM D 3574, Test E) of 7 lb/in². Forthermal properties, the foam material has a thermal conductivity (ASTM C518 at mean temperature of 75° F.) of 0.32 (BTU·in)/(hr·ft³·° F.), and acontinuous use temperature (recommended maximum) of 575° F. Forflammability properties, the foam material has a radiant panel flamespread index (ASTM E 162) of 1, a non-flaming specific optical density(ASTM E 662) of smoke of 1, a flaming specific optical density of smoke(ASTM E 662) of 3, a flame spread index (ASTM E 84-95, Tested at athickness of 22 mm (0.9 in.)) of 0, a smoke developed index (ASTM E84-95, Tested at a thickness of 22 mm (0.9 in.)) of 10. For steamautoclave aging properties (ASTM D 3574, Test J, Procedure J, and TestE), the foam material has a tensile strength retained of greater than85% and a change in weight and dimensions of less than 3%. For acousticproperties, the foam material has the following acoustical absorptioncoefficients (sabins/ft²; ASTM C 423 and E 795, Type A Mounting) at 1in.: 0.08 at 125 Hz, 0.22 at 250 Hz, 0.58 at 500 Hz, 0.93 at 1000 Hz,0.94 at 2000 Hz, 0.81 at 4000 Hz. The foam material has the followingacoustical absorption coefficients (sabins/ft²; ASTM C 423 and E 795,Type A Mounting) at 2 in.: 0.34 at 125 Hz, 0.52 at 250 Hz, 0.86 at 500Hz, 1.06 at 1000 Hz, 0.85 at 2000 Hz, 0.94 at 4000 Hz.

The annular director plate 340 is a thin, annular sheet of polycarbonatematerial that serves as a barrier and directs air flow towards thecenter of the quiet exhaust assembly module 270.

The annular foam air diffuser 350 serves to break up some line of sightin the quiet exhaust assembly module 270 and attenuate the air flowsound waves. The annular foam air diffuser 350 is made of a reticulatedflexible polyester urethane foam that has a completely open cell,three-dimensional structure of skeletal strands which give them specialfiltering properties. The foam material used in the diffuser 350 is soldas 20 PPI, SIF Z under the name FOAMEX® by Foamex Technical Products ofEddystone, Pa. The homogeneous structure of the diffuser 350 helpsminimize the possibility of open channels which could drastically affectfilter efficiency. Each cell in the medium is completely interconnectedwith all surrounding cells. This allows for free passage of air and atthe same time provides high surface-area contact for impingement of dustparticles. The resilience and strength of the diffuser 350 helps preventand strand displacement under normal operating conditions. In theembodiment shown, the diffuser 350 includes a 20 pore size (averagenumber of pores-per-linear-inch). At this porosity, the diffuser 350includes a density of 1.9 lb/ft3, a tensile strength of 25 psi, anultimate elongation of 320%, a tear strength of 5.5 lb/in., a 50%compression set of 7, a 25% compression deflection of 0.42 psi, and a65% compression deflection of 0.67 psi. The diffuser 350 has excellenthigh-temperature characteristics. It can withstand intermittenttemperatures as high as 225° F. At temperatures above 500° F., thematerial beings to melt with decomposition and vaporization.

The annular acoustic panel 360 is made of the same material as theacoustic panel 330 described. The above description of the material usedin the acoustic panel 330 is incorporated by reference here as thoughset forth in full.

The quiet module cap 370 includes a circular dish-like configurationwith an annular recess that receives the acoustic panel 360. A centralboss 399 receives threaded fastener 400 to mount the quiet module cap370 and hold the intermittent components of the quiet module housing 320together. The quiet module cap 370 is made of a polycarbonate materialand includes eight (8) Stage 3 slots 402 having a dimension of 2.0in.×0.36 in. (8 Slots @ 2.00″×0.36 in =5.76 sq. in.). Stage 3 air flowoccurs through these slots 402. As indicated above, the total area ofthe Stage 3 slots 402 is 5.76 sq. in. The quiet module cap 370 andthreaded fastener 400 allow the quiet exhaust assembly module 270 to beeasily field serviced. To service the quiet exhaust assembly module 270,a user simply unscrews the threaded fastener 400, and removes the quietmodule cap 370. This provides easy access to the components of the quietexhaust assembly module 270 for repair or replacement of the components.The entire quiet exhaust assembly module 270 can also be easily replacedin this manner. As a result, the backpack vacuum cleaner 100 is neverdown because of something in the quiet exhaust assembly module 270 ofthe backpack vacuum cleaner 100.

A motor control module 410 is electrically coupled to the vacuum motor290, two-speed switch assembly with switch box 230, and power cordassembly 240. The motor control module 410 provides two-speed control ofthe vacuum motor 290. The motor control module 410 also includes athermal protection device for shutting off the vacuum motor 290 when thetemperature exceeds approximately 95° C.

The backpack vacuum cleaner 100 will now be described in use. When theuser is in the area desired for vacuuming, the user dons the backpackvacuum cleaner 100 using the backpack strap system 160 in the samemanner as putting on a backpack for hiking. This is easily performedbecause the backpack vacuum cleaner 100 is light-weight (2-12 lbs.). Inthe embodiment shown, the vacuum cleaner assembly 110 weighs 11 lbs., 3oz. The user's arms are placed through the shoulder straps 180 and theshoulder straps 180 are tightened to a snug, yet comfortable conditionon the user's shoulders. The waist belt 190 is clipped together, andtightened to a snug, yet comfortable condition around the user's waist.Prior to or after donning the backpack vacuum cleaner 100, the plug ofthe power cord assembly 240 is plugged into an electrical outlet. In anembodiment of the backpack vacuum cleaner 100 where the backpack vacuumcleaner 100 has an onboard power source (e.g., one or more batteries,fuel cells), plugging the power cord assembly 240 into an electricaloutlet to power the backpack vacuum cleaner 100 may not be necessary.The backpack vacuum cleaner 100 is switched on using the two-speedswitch assembly 230. The two-speed switch assembly 230 is also used tocontrol the speed of the vacuum motor 290 between a high setting and lowsetting. In alternative embodiments, the backpack vacuum cleaner 100 mayhave a number of settings other than two settings (e.g., 1, 3, 4, etc.).

In the embodiment shown, the backpack vacuum cleaner 100 performs (about70 CFM with about 70 in. (H₂O) of lift @ about 65 dbA on a high-speedmotor setting, and about 40 CFM with about 40 in. (H₂O) of lift @ about61 dbA on a low-speed motor setting. In a preferred embodiment, thebackpack vacuum cleaner 100 includes a flow rate (CFM) to noise (dbA)ratio (flow rate/noise) of at least 0.6 and a suction (in. (H₂O)) tonoise (dbA) ratio (suction/noise) of at least 0.6. In a more preferredembodiment, the backpack vacuum cleaner 100 includes a flow rate (CFM)to noise (dbA) ratio (flow rate/noise) of at least 1.0 and a suction(in. (H₂O)) to noise (dbA) ratio (suction/noise) of at least 1.0.

With the vacuum motor 290 activated, air, dirt, and debris are drawnthrough the vacuum cleaner floor tool 150, vacuum cleaner wand 140,vacuum cleaner hose 130, and air inlet 210 into the intake filter/refusebag 265 (FIG. 3). The dirt and debris is collected by the intakefilter/refuse bag 265 and air is drawn through the motor intake filter280 and the vacuum motor 290. Exhaust air is expelled out of the bottomof the vacuum motor 290, and into the motor housing 310. The exhaust airreflects off of and is directed radially outward along the star-shaped,radiating ridges on the top surface 392. The exhaust air exits the motorhousing 310 through the Stage 1 slots 396. The exhaust air reflects offof the acoustic panel 330, dampening the sound level, around the bottomof the motor housing 310 and top of the quiet module housing 320, andinto/through the Stage 2 slots 396 of the quiet module housing 320. Theair then flows downward towards the director plate 340, and the directorplate 340 directs the air flow radially inward and down towards theacoustic panel 360. Air flow reflects off of the acoustic panel 360,further dampening the sound level, and outward through the air diffuserfoam 350. The air diffuser foam 350 filters out exhaust particulates inthe exhaust air flow and further dampens the sound levels withoutsignificantly impeding air flow. The exhaust air impinges the acousticpanel 410 as it exits the air diffuser foam. The exhaust air then flowsdownward, through the stage 3 slots 402, and out of the quiet exhaustassembly module 270.

With reference to FIGS. 2, 5, and 6, the air inlet 210 has a 1.5 in.intake diameter and an intake area of 1.77 sq. in. As indicated above,the total bypass area for the Stage 1 slots 384 is 7.125 sq. in., thetotal bypass area for the Stage 2 slots 396 is 6.0 sq. in., and thetotal bypass area for the Stage 3 slots 402 is 5.76 sq. in. Theinventors have determined that it is desirable for the bypass areas ineach stage of the quiet exhaust assembly module 270 to be at least 3times that of the area of the air inlet 210. This reduces friction and,thus, minimizes flow loss.

The exhaust assembly module 270 incorporates the principles of “Line ofSight” and non-reflective surfaces to diminish sound levels (db). In thequiet exhaust assembly module 270, the vacuum motor 290 is encapsulatedin a housing, and air flow is directed to high-temperature acoustic foamcovered surfaces and through a condensed labyrinth of passages.

The above features minimize the weight of the backpack vacuum cleaner100, maximize dissipation of sound levels in the backpack vacuum cleaner100, and maximize air flow in the backpack vacuum cleaner 100.

The above description of the disclosed embodiments is provided to enableany person skilled in the art to make or use the invention. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the generic principles described herein can beapplied to other embodiments without departing from the spirit or scopeof the invention. Thus, it is to be understood that the description anddrawings presented herein represent a presently preferred embodiment ofthe invention and are therefore representative of the subject matterwhich is broadly contemplated by the present invention. It is furtherunderstood that the scope of the present invention fully encompassesother embodiments that may become obvious to those skilled in the artand that the scope of the present invention is accordingly limited bynothing other than the appended claims.

1. A light-weight, quiet vacuum cleaner assembly for a backpack vacuumcleaner including a backpack assembly for carrying the vacuum cleanerassembly on a user's back, a vacuum cleaner hose for vacuuming debrisfrom a surface, and a filter for filtering out vacuumed debris,comprising: an air inlet for communicating with the vacuum cleaner hoseand the filter; a vacuum motor for drawing air through the vacuumcleaner hose, air inlet, and filter; a quiet exhaust assembly module incommunication with the vacuum motor for expelling and quieting exhaustfrom the vacuum motor, wherein the vacuum cleaner assembly weighs 2-12lbs. and includes a flow rate (CFM) to noise (dbA) ratio (flowrate/noise) of at least 0.6.
 2. The light-weight, quiet vacuum cleanerassembly of claim 1, wherein the vacuum cleaner assembly includes a flowrate (CFM) to noise (dbA) ratio (flow rate/noise) of at least 1.0. 3.The light-weight, quiet vacuum cleaner assembly of claim 1, wherein thevacuum cleaner assembly includes a suction (in. (H₂O)) to noise (dbA)ratio (suction/noise) of at least 0.6.
 4. The light-weight, quiet vacuumcleaner assembly of claim 3, wherein the vacuum cleaner assemblyincludes a suction (in. (H₂O)) to noise (dbA) ratio (suction/noise) ofat least 1.0.
 5. A light-weight, quiet vacuum cleaner assembly for abackpack vacuum cleaner including a backpack assembly for carrying thevacuum cleaner assembly on a user's back, a vacuum cleaner hose forvacuuming debris from a surface, and a filter for filtering out vacuumeddebris, comprising: an air inlet for communicating with the vacuumcleaner hose and the filter, the air inlet including an intake area; avacuum motor for drawing air through the vacuum cleaner hose, air inlet,and filter; a quiet exhaust assembly module in communication with thevacuum motor for expelling and quieting exhaust from the vacuum motor,wherein the quiet exhaust assembly module includes a stage of exhaustopenings having a total area and the ratio of the total area of thestage of exhaust openings to the intake area of the air inlet is atleast 3:1.
 6. The light-weight, quiet vacuum cleaner assembly of claim5, wherein the quiet exhaust assembly module includes a motor housingwith the stage of exhaust openings therein.
 7. The light-weight, quietvacuum cleaner assembly of claim 5, wherein the quiet exhaust assemblymodule includes a second stage of exhaust openings having a total areaand the ratio of the total area of the second stage of exhaust openingsto the intake area of the air inlet is at least 3:1.
 8. Thelight-weight, quiet vacuum cleaner assembly of claim 7, wherein thequiet exhaust assembly module includes a quiet module housing with thesecond stage of exhaust openings therein.
 9. The light-weight, quietvacuum cleaner assembly of claim 5, wherein the quiet exhaust assemblymodule includes a third stage of exhaust openings having a total areaand the ratio of the total area of the third stage of exhaust openingsto the intake area of the air inlet is at least 3:1.
 10. Thelight-weight, quiet vacuum cleaner assembly of claim 9, wherein thequiet exhaust assembly module includes a quiet module cap with the thirdstage of exhaust openings therein.
 11. The light-weight, quiet vacuumcleaner assembly of claim 5, wherein the vacuum cleaner assembly weighs2-12 lbs. and includes a flow rate (CFM) to noise (dbA) ratio (flowrate/noise) of at least 0.6.
 12. The light-weight, quiet vacuum cleanerassembly of claim 5, wherein the vacuum cleaner assembly weighs 2-12lbs. and includes a flow rate (CFM) to noise (dbA) ratio (flowrate/noise) of at least 1.0.
 13. The light-weight, quiet vacuum cleanerassembly of claim 5, wherein the vacuum cleaner assembly weighs 2-12lbs. and includes a suction (in. (H₂O)) to noise (dbA) ratio(suction/noise) of at least 0.6.
 14. The light-weight, quiet vacuumcleaner assembly of claim 5, wherein the vacuum cleaner assembly weighs2-12 lbs. and includes a suction (in. (H₂O)) to noise (dbA) ratio(suction/noise) of at least 1.0.
 15. The light-weight, quiet vacuumcleaner assembly of claim 5, wherein the quiet exhaust assembly moduleincludes a light-weight, high-temperature, fire retardant foam materialhaving a density no greater than 0.4 lb/ft³ to attenuate the exhaustsound.
 16. The light-weight, quiet vacuum cleaner assembly of claim 15,wherein the light-weight, high-temperature, fire retardant foam materialis a high-performance polyimide foam.
 17. The light-weight, quiet vacuumcleaner assembly of claim 5, wherein the quiet exhaust assembly moduleincludes a light-weight foam air diffuser having a density no greaterthan 1.9 lb/ft³ to attenuate the exhaust sound and filter out exhaustparticles.
 18. The light-weight, quiet vacuum cleaner assembly of claim17, wherein the light-weight foam air diffuser is a reticulated flexiblepolyester urethane foam.
 19. The light-weight, quiet vacuum cleanerassembly of claim 5, wherein the quiet exhaust assembly module includesan outer acoustic panel surrounding substantially all of the quietexhaust assembly module, the acoustic panel including an outer surfacewith a polycarbonate sheet laminated thereto, and the polycarbonatesheet including hoop stress therein that causes the acoustic panel to beheld in place, surrounding substantially all of the quiet exhaustassembly module, without any adhesive.
 20. A light-weight, quiet vacuumcleaner assembly for a backpack vacuum cleaner including a backpackassembly for carrying the vacuum cleaner assembly on a user's back, avacuum cleaner hose for vacuuming debris from a surface, and a filterfor filtering out vacuumed debris, comprising: an air inlet forcommunicating with the vacuum cleaner hose and the filter; a vacuummotor for drawing air through the vacuum cleaner hose, air inlet, andfilter; a quiet exhaust assembly module in communication with the vacuummotor for expelling and quieting exhaust from the vacuum motor, whereinthe vacuum cleaner assembly weighs 2-12 lbs. and includes a suction (in.(H₂O)) to noise (dbA) ratio (suction/noise) of at least 0.6.